Deus Ex: Human revolution
Before we start, I should tell you that I was one of those who found the first Deus Ex to be a bit overrated. Not bad, mind you, just not worth all the hype. I found that System Shock 2 did the statbased shooter better, and the stealth mechanics of Deus Ex was clumsy, in part due to enemies being a bit inconsistent in when they could spot you and when they could not. Deus ex 2 was just uninteresting and rather boring.

Deus Ex: Human revolution takes place a few years before the first Deus Ex, when human augmentation (as they call it, basically advanced cybernetics) has reached a point where it divides people into two camps, those who are pro-augmentation, who think that it is the natural next step for humanity, and those who are against it, who claim that augmentations will ruin us of our humanity. You are one of those augmented people, who after an attack on the lab that you were working in gets some of the most advanced cybernetics ever created. After 6 months of recovery, your company gets attacked again, and you get called into duty. From here you have to find out what happened, who did this, why they did this and of course do something about it. Things are never that easy, and anyone who played the original Deus Ex knows what to expect.

Graphics
The graphics in this game looks quite good, even on a weaker system. Some of the animations can seem a bit off, which is more obvious during the many dialogue sequences. The game has a very consistent art style, one that really fits the setting as a whole, and even though you get to travel to several different places around the world, it still manages to feel coherent. It does at places clash a bit with the artistic style of Deus Ex 1, though as that takes place 30 years into the future, that is to be expected. One thing that does seem a bit odd is how cybernetics is portrayed though, it feels more sleek & streamlined in Human Revolution, even though it is supposed to be far more primitive.

Sound
Most sound effects work well, and the voice acting is surprisingly good. Most of the characters feel believable and have voices that works well for them. Generic NPCs have voices that repeats a bit too often, but that is a minor issue. Much like in Vampire the masquerade: Bloodlines there are radios & TVs scattered around the world, which fills you in on certain peoples view on the events that transpires, from the more serious news report, to conspiracy nuts on the radio. These added a nice touch, and were quite entertaining to listen to (in particular some of the more outlandish conspiracy theories, which sounded like something straight out of a youtube conspiracy video)

Gameplay
This is where Deus Ex HR shines. The stealth mechanics works really well in this game, you can easily figure out how well hidden you are, and if you run the risk of being spotted. The game actively encourages you to use stealth, as it gives you more experience for a stealthy takedown (to get the most, you should get up close and personal with the enemy, knocking them out in melee) . The gunplay felt like it worked well, though I only ever used it during the bosses, as I played through the game without killing a single non-boss enemy.
The level design was quite open, offering many different paths to most locations. It was not uncommon for me to find two different entry points from the outside, then enter the location, and once on the inside find 3 more possible points of entry. And the game actively rewards exploration, giving you both experience and a few goodies to pick up for taking the less obvious rout. This was probably a good design choice, as it emphasis stealth and mind over pure gunplay, which probably helped quite a few people to play the game as intended, instead of just as a decent shooter.
There is also a hacking minigame, which sees heavy use during the game. At first glance it might look like it is a lot to do in it, but in reality it is rather simple, and to a large degree luck based. Not the best part of the game, but still one of the better hacking minigames that I've seen to date.
As you gain experience, you are allowed to level up different abilities. There is a good variety of abilities, some focused on hacking, some on stealth, some on dealing damage, and a few oddball ones, like the ability to break down walls, or jump really high. Sadly the balance between these did not seem all that great. A few were incredibly useful, like the ones preventing detection while hacking, while some were less useful, like the ability to ignore flashbangs. There was even a totally pointless tree, which felt like something that they forgot to take out after doing some changes to the hacking minigame.

The bad
We have all heard about the bosses. They stink. At least there are not a whole lot of them, but they just don't fit into the game at all. At least they were not very hard, even if you had not spent any points in combat augmentations (I don't see why some reviewers complained about how their lack of proper augmentations made these nigh impossible, I died twice against the first boss, and not a single time during any of the following bosses).
The game also showers you with experience points, which makes augmentation choices less more a question on "when" than "if". By the end of the game, I had all augmentation options that seemed useful, almost all that seemed to have some use, and even some that seemed totally useless (and they were actually totally useless). This watered down the experience a tad bit, but it was not a gamebreaker.

Overall, I was quite impressed by this game. The story was interesting, the stealth mechanics worked really well (though I would have preferred leaning to the cover mechanics) and the level design was very good. The game had a few minor issues, but nothing that seriously detracted from the experience. Overall I think that this game was superior to the original Deus Ex, but a surprisingly wide margin. Now let's hope that they are as good to Thief.